Project Summary This project proposes to take the first step in the development of a compact liquid-helium (LHe)- free 1-GHz HTS magnet for high-resolution microcoil NMR spectroscopy. In this age of shrinking resources?funding and LHe?and of ever progressing probe technologies, we believe that this microcoil NMR spectroscopy is poised to take full advantage of the phenomenal advances currently taking place in the standard 54-mm bore ?1-GHz NMR magnet. A microcoil NMR magnet is compact and thus its cost will be less by nearly an order of magnitude than that of the standard NMR magnet, and placeable on a bench, thereby resulting in a large saving in space. Also, LHe-free operation enables the user to be independent from a cooling source in short supply. Through this project we demonstrate that our innovative design concepts incorporated in the proposed prototype magnet are viable for the next generation tabletop liquid- helium-free ?1-GHz NMR magnets. The specific aims are to: 1) design and construct a prototype single-coil all-REBCO 23.5-T/20-mm cold-bore magnet, and achieve a field of 23.5 T at 10 K in a volume of solid nitrogen (SN2); 2) validate a screening-current-inducing field (SCF) reduction method for enhancing field quality; 3) apply an iron yoke design to reduce a 5-gauss fringe field radius; and 4) design an shielded tabletop LHe-free 23.5-T/25-mm RT-bore high- resolution NMR magnet, incorporating field-shimming techniques being developed for our 1.3- GHz high-resolution NMR magnet. The innovative and challenging design and operation concepts of the prototype 23.5-T tabletop magnet include: 1) an all-HTS (REBCO) composition; 2) operation at 10 K, thus almost by definition LHe-free, the first ever >4.2-K operation among all high-field (>10 T) superconducting magnets; 3) No-Insulation (NI) winding technique that makes a magnet compact, mechanically robust, and self-protecting; and 4) a single, rather than multi-nested, coil formation that leads, compared with the traditional high-field NMR magnet, to simpler manufacturing processes, which in turn, will result in a more affordable, high-field NMR magnet occupying a smaller footprint. The enabling features will become viable for the next generation high-resolution ?1-GHz NMR, that is compact, helium-free, stable, and affordable, thereby enabling new, high-impact applications of superconductivity to biomedical research.